1. Field of the Invention
The present invention relates to a method of enhancing contrast of an image. More particularly, according to the present invention, histogram distribution is calculated based on an image that has been photographed or read out from a storage medium, the type of the image is determined according to the contrast state of the image, the movement directions of control points of a 3-D Bezier curve is determined according to the type of the image, and the movement distances of the control points of the 3-D Bezier curve are calculated based on the number of luminance values of the histogram distribution. Two control points of the 3-D Bezier curve are moved based on the movement directions and the movement distances of the control points, and the 3-D Bezier curve is created by using the two moved control points and two fixed control points. Then, the contrast of the image is enhanced by applying the Bezier curve.
2. Description of the Related Art
Contrast exerts a significant influence to image quality when a person visually recognizes an image. If the contrast of an image is enhanced, the image may be more easily interpreted and recognized by the person and may serve as “more appropriate input data” for other automatic image processing technologies. The main purpose of the image enhancement is to create an image more suitable for a given work and a specific observer by changing image attributes. Through such image processing, at least one attribute may be changed.
In general, image contrast is defined as the range of usable luminance intensities of a given image. The image contrast may be expressed through following equation 1 mathematically.Contrast=(Lmax−Lmin)/(Lmax+Lmin)  Equation 1
Herein, the Lmax and Lmin represent the maximum luminance value and the minimum luminance value of the given image, respectively.
A contrast enhancement scheme is an image processing technology of making image features as more clear values by using the maximum range of luminance intensity provided by bit numbers used for the quantification of the luminance intensity.
Among contrast enhancement schemes having the above characteristics, a contrast enhancement scheme optimized to the eyes of the person is required.